Guillaume Rufin

The four-time Grand Slam champion lost to 18-year-old Laura Robson of Britain in the second round of the U.S. Open on Wednesday, and will head into retirement after she finishes playing in doubles at Flushing Meadows.

The U.S. Tennis Association announced its eight men’s wild cards on Tuesday. Hewitt is a two-time major champion — winning the 2001 U.S. Open — but at age 31 the Australian has fallen to 134th in the world.